Engine starter gearing



- July 8, 1952 J. E. Bux'roN ENGINE STARTER GEARING Filed April 5, 1951INVENTOR. ja/nes 6A/7am TRNEY WITNESS.'

Patented July 8, 1952 v IPE-'Nif f v@Delaware Application'Apil 5, 1951,Serial No. 219,427

comms. (ci. --74-1) The presenti invention'relatesftoenginel'starterdigearirig, -and Lmore .particularly .Arto that" type in .fis effective:and reliable in: 'operation land; simple aand:V economicalv in.'construction.

in which the mechanical meshing means-for the pinion operatesv`positively but quietly and without shock.

It is another object -tofprovide such a device in which the meshing androtating means includes a coiled spring which serves both as a clutchingmeans and as a mesh-enforcing means.

Further objects and advantages will be apparent from the followingdescription taken in connection with the accompanying drawing in which:

Fig. 1 is a side elevation partly broken away and in section of astarting system constituting a preferred embodiment of the invention,the electrical elements being shown diagrammatically; and

Fig. 2 is a detail on an enlarged scale in side elevation, partly brokenaway and in section showing the mechanical traversing mechanism for thestarting pinion.

In Fig. 1 of the drawing there is illustrated a starting motor indicatedgenerally by the numeral I, the armature 2 of which is shiftable axiallyso as to move the power shaft 3 thereof longitudinally. A spring 4operating on a, slidable plunger 5 normally maintains the armaturedecentered to the right with relation to the field coils 6 of the motoras illustrated. A latch 1 is arranged to restrain the plunger 5 fromurging the armature into decentered position except when released by atrip 8 actuated by opening the starting switch 9.

The structure for controlling the longitudinal movement of the armatureshaft is the same and operates in the same manner as that illustrated inthe patent to Buxton 2,394,531, so that further description thereof isdeemed unnecessary.

Pinion II is slidably journalled on the armature shaft 3 for movementthereon and therewith into mesh with a gear I2 of the engine to bestarted. Means for sliding the pinion along the armature shaft isprovided comprising a screw shaft I3 fixed as indicated at I4 on thearmaturev shaft, a control nut I5 threaded on the screw shaft, and abarrel member I6 surrounding the -A screw/shaftvr and control nut.y .Thecontrol .nutfv I5 -isr` provided with a radial flange I'Il andra-cylin-.drcal surfacev l-.adjacent thereto. .The .pinion II- .has adriven-coupling member IS'Xed thereon in anyV suitable manner, having Aaradial ian'ge 2I and a cylindrical vsurface` 22 similar'to "the surface'I8 of the controlnut.

A cylindrical compression and'torsionfspring l23'is seatedv atitsends onthe surfacesI-'B and 22 of thev control 1 nutY and coupling memben--and:is

'l maintained underinitial endwise compressicnbevtween the flangesI1-and22l of Vsaidl-rnei'nbersvby 1l means of .i an internal i'shoulder24` 'oftheibarrel which limits endwise movement'of-'.thecontro1 nutAwithin the barrel, and a lock ring 25 retained in the open end of thebarrel as indicated at 26 and serving as a back stop for the couplingmember I9.

The barrel I6 has an inturned flange 2l which` is arranged to engage theend of the screw shaft I3 to limit the meshing movement of the barreland pinion on the armature shaft; and an antidrift spring 28 is providedin the barrel located between the flange 2l and a shoulder 29 on thescrew shaft so as to normally maintain the parts in idle position asillustrated, with the control nut in engagement with the ends of thethreadsv of the screw shaft.

In operation, when the starting motor is energized, the mutualattraction of the armature and eld causes the armature to center itselfwith respect to the eld coils so as to move the shaft 3 to the left,thereby bringing the end of the pinion I I to the dotted line position(A) as shown in Fig. 2 where it is in initial meshing relation with theengine gear I2. If, during this longitudinal movement of the pinion, apinion tooth should abut against a tooth of the engine gear, themovement of the pinion is momentarily arrested, causing the spring 23'to be compressed until the torque of the armature transmitted throughthe threaded connection andthe spring 23 indexes the pinion into properregistry with the tooth spaces of the engine gear. The spring 23thereupon expands and propels the pinion toward meshed position.Rotation of the armature then commences and is transmitted to the screwshaft I3, which causes the control nut I5 to be further traversed to theleft, moving the pinion Il and barrel I6 by compression of spring 23until the pinion reaches the fully meshed position indicated by thedotted line (B), whereupon the longitudinal movement of the pinion isarrested by the engagement of the barrel flange 27 with the end of thescrew shaft I3. v

The spring 23 is then further compressed by the control nut l5, and iscaused to wrap down on the cylindrical surfaces IB, 2'2 of the controlnut and coupling member I9 so as to yieldingly couple these memberstogether and transmit the cranking torque to the pinion.

When the engine starts, the acceleration of the pinion causes the spring23 to move the vcontrol nut back in the barrel I6 against the shoulder24, at which time the spring is permitted to unwrap and the pinion canoverrun freely except for the small amount of friction between the endof the spring 23 and the flange 2| of the coupling member. The spring 23is thus arranged to combine the functions of a mesh-enforcing spring, ayielding driving connection, and an overrunning clutch.

If the engine does not continue to be selfoperative, as soon as therotation of the engine gear is retarded to correspond with that of thepinion, the cranking operation will be resumed. When a successful starthas been secured, the release of the starting switch 9 -by the operatordeenergizesthe starting motor and trips the latch 1, permitting theparts to -return to their normal idle positions Where they are retainedby the spring-pressed plunger V5.

Although but one embodiment of the invention has been shown anddescribed in detail, it willgo be understood other embodiments arepossible and changes may be made in the design and arrangement of theparts Without departing from the spirit of the invention.

I claim:

1. Starter gearing for internal combustion engines including alongitudinally shiftable shaft, a screw shaft fixed thereon, a controlnut and driving clutch member threaded on the screw shaft having asmooth cylindrical clutch surface, a pinion slidably journaled on thepower shaft, a driven clutch mem-ber xedzto the pinion having acylindrical surface lsimilar to that of the driving clutch member, a,coiled spring seated at its ends on said cylindrical surfaces, wound inthe direction to wrap down and grip theV cylindrical surfaces whencramping torque is transmitted therethrough, a barrel member surroundingthe `clutch members limiting their separation and having a terminalflange which engages the end of the screw shaft to limit the travel ofthe clutch members and pinion thereon,

and means for shifting the power'shaft to move the pinion into and outof initial meshing engagement `with a gear of theengine to be started.

2. Starter gearing as set forth in claim 1 in which the driving anddriven clutchmembers each have a radial ange, and the clutch springengages the anges to yieldingly maintain the clutch members in extendedrelation.

3. Starter gearing as set forth in claim 2 in which the driven clutchmember is slidably received in the barrel so as to compress the clutchspring when the meshing movement of the pinion is arrested.

JAMES E. BUXTON.

No references cited;

